Code examples for creating Caldera Forms add-on UI, excerpted from https://calderawp.com/downloads/braintree-for-caldera-forms/

config.php

<?php

//////////////////////////////////////////////////////////////////////////
//This is the config.php file that generates the processor admin UI /////
////////////////////////////////////////////////////////////////////////
//When you register your processor on the caldera_forms_get_form_processors filter, you set an argument for "template" with the path to this file.


if ( class_exists( 'Caldera_Forms_Processor_UI' ) ) {
	//show an SSL required notice if is_ssl() is false
	echo Caldera_Forms_Processor_UI::ssl_notice( 'Braintree for Caldera Forms' );

	//get the field  configuration
	$cf_braintree_config_fields = cf_braintree_config_fields();

	//get HTML for UI
	$config_fields              = Caldera_Forms_Processor_UI::config_fields( $cf_braintree_config_fields );

	//echo UI
	echo $config_fields;
	
}

functions.php

<?php
///////////////////////////////////////////////////////////////////////////////////////////////////
//this is the fields config function that is in the functions.php file of our BrainTree add-on/////
///////////////////////////////////////////////////////////////////////////////////////////////////


/**
 * The fields we need for this proccesor
 *
 * @since 0.1.0
 *
 * @return array
 */
function cf_braintree_config_fields() {
	$fields = array(
		array(
			'id'   => 'sandbox',
			'label' => __( 'Test Mode', 'cf-braintree' ),
			'type' => 'checkbox',
			'required' => false,
		),
		array(
			'id'   => 'braintree_merchant_id',
			'label' => __( 'Merchant ID', 'cf-braintree' ),
			'desc' => __( 'Enter your unique merchant ID (found on the portal under API Keys when you first login).', 'cf-braintree' ),
			'type' => 'text',
			'magic' => false,
		),
		array(
			'id'   => 'braintree_merchant_account_id',
			'label' => __( 'Merchant Account ID', 'cf-braintree' ),
			'desc' => __( 'Enter your unique merchant account ID (found under Settings > Processing > Merchant Accounts).', 'cf-braintree' ),
			'type' => 'text',
			'magic' => false,
		),
		array(
			'id'   => 'braintree_public_key',
			'label' => __( 'Public Key', 'cf-braintree' ),
			'desc' => __( 'Enter your public key (found on the portal under API Keys when you first login).', 'cf-braintree' ),
			'type' => 'text',
			'magic' => false,
		),
		array(
			'id'   => 'braintree_private_key',
			'label' => __( 'Private Key', 'cf-braintree' ),
			'desc' => __( 'Enter your private key (found on the portal under API Keys when you first login).', 'cf-braintree' ),
			'type' => 'text',
			'magic' => false,
		),
		array(
			'id' => 'orderID',
			'label' => __( 'Order ID', 'cf-braintree' ),
			'required' => false,
		),
		array(
			'id' => 'submitForSettlement',
			'label' => __( 'Submit For Settlement Immediately?', 'cf-braintree' ),
			'required' => false,
			'type' => 'checkbox'
		),
		array(
			'id'   => 'amount',
			'label' => __( 'Price', 'cf-braintree' ),
		),
		array(
			'id'   => 'cardholderName',
			'label' => __( 'Cardholder Name', 'cf-braintree' ),
		),
		array(
			'id'   => 'card_number',
			'label' => __( 'Card Number', 'cf-braintree' ),
		),
		array(
			'id'   => 'card_exp_month',
			'label' => __( 'Expiration Month', 'cf-braintree' ),
		),
		array(
			'id'   => 'card_exp_year',
			'label' => __( 'Expiration Year', 'cf-braintree' ),
		),
		array(
			'id'   => 'card_cvc',
			'label' => __( 'CVV Code', 'cf-braintree' ),
		),
		array(
			'id'   => 'first_name',
			'label' => __( 'Customer First Name', 'cf-braintree' ),
		),
		array(
			'id'   => 'last_name',
			'label' => __( 'Customer Last Name', 'cf-braintree' ),
		),
		array(
			'id'   => 'customer_email',
			'label' => __( 'Customer Email', 'cf-braintree' ),
			'allow_types' => 'email',
			'exclude' => 'system'
		),
		array(
			'id'   => 'card_address',
			'label' => __( 'Street Address Line 1', 'cf-braintree' ),
			'required' => false,
		),
		array(
			'id'   => 'card_address_2',
			'label' => __( 'Street Address Line 2', 'cf-braintree' ),
			'required' => false,
		),
		array(
			'id'   => 'card_city',
			'label' => __( 'City/ Locality', 'cf-braintree' ),
			'required' => false,
		),
		array(
			'id'   => 'card_state',
			'label' => __( 'State/ Providence/ Region', 'cf-braintree' ),
			'required' => false,
		),
		array(
			'id'   => 'card_zip',
			'label' => __( 'Zip Code/ Postal Code', 'cf-braintree' ),
			'required' => false,
		),
		array(
			'id'   => 'card_country',
			'label' => __( 'Country Code', 'cf-braintree' ),
			'required' => true,
		),
	);

	return $fields;

}